Page 87 - MSAM-3-2

Materials Science in Additive Manufacturing Sustainable resin for coral restoration

The wavelength of the ultraviolet (UV) light source is
405 nm. After polymerization, the coral plugs were lifted
off the building platform, soaked, and washed in 70%
isopropanol for 30 min to remove unpolymerized ink and
photoinitiator. Subsequently, the coral plugs were cured
for 60 min at 40°C in the Formlab UV curing machine to
enhance the mechanical strength of the structures.
2.2. Material characterizations
2.2.1. Fourier transform infrared (FTIR) spectroscopy
A FTIR spectrometer (FTIR-Nicolet iS50R, Thermo
Scientific Instrument, USA) equipped with a built-in wide-
range diamond ATR was used to analyze the AESO sample
before and after curing. The scan range was between 400
-1
-1
Figure 1. Schematic illustration of commercial coral plugs with and 3800 cm with a resolution of 5 cm .
dimensions.
2.2.2. Scanning electron microscopy
available coral plugs that are made of ceramic. Computer- The surface morphology of the printed CCP scaffold was
aided design (CAD) software was utilized to design the analyzed using a scanning electron microscope (SEM;
model for printing. Zeiss Merlin SEM-61-95, Zeiss, Germany) operating
2.1.1. Preparation of AESO resin under a 5.0 kV accelerating voltage electron beam. Before
imaging, the samples were sputter-coated with gold to
The process of preparing the AESO resin can be described as dissipate the charge that builds up during SEM imaging.
follows: 80 g of AESO (containing 4000 ppm monomethyl The gun vacuum and system vacuum were maintained at
ether hydroquinone as an inhibitor; Sigma-Aldrich, USA) 9.26 × 10 mbar and 1.37 × 10 mbar, respectively. The
−5
−10
was mixed with 80 mL of acetone (HPLC grade) and 20 g current probe (I Probe) was set to 100 pA.
of 1,6-hexanediol diacrylate (Sigma-Aldrich, USA). The
mixture was stirred thoroughly to achieve a homogeneous 2.2.3. Water contact angle
solution. Then, 1.25 g of bis(2,4,6trimethyl benzoyl)- The surface wettability of the printed CCP scaffold was
phenylphosphineoxide (Irgacure 819; Sigma-Aldrich,
USA) was added to the solution. The mixture was stirred assessed using a contact angle analyzer (DSA100E, Kruss-
until the photoinitiator was fully dissolved and then placed Scientific, Germany). Approximately 2.2 µL of deionized
in a vacuum chamber for 2 days to remove the solvent. The water was dispensed onto the surface of the samples. The
resulting yellow resin can be used for 3D printing (referred entire process of water deposition and sample absorption
to as AESO resin). was recorded. The first image captured after water
deposition was utilized for static water contact angle
2.1.2. Preparation of modified CCP resin measurements. The measurements were conducted at
The AESO resin, weighing 100 g, was thoroughly mixed room temperature and repeated 6 times for accuracy.
with 43 g of fine calcium carbonate powder (particle size 2.2.4. Thermogravimetric analysis (TGA)
≤50 µm, with a purity of 98%; Thermo Scientific, USA).
The ratio of AESO resin to calcium carbonate is 7:3. The The decomposition of the printed AESO and CCP
resulting resin, which appeared white/yellowish in color, scaffold was analyzed using a TGA analyzer (Discovery
was utilized for 3D printing. The size of the filler particles TGA 5500, TA Instruments, USA). Initially, the sample
(calcium carbonate) needs to be smaller than the height was equilibrated at a temperature of 50°C and then
of each printing layer to ensure successful printability. In heated from 50°C to 900°C at a programmed ramp rate
addition, the selection of the specific calcium carbonate of 10°C/min. The heating process was conducted in a
type is significant. It was found that finer calcium carbonate nitrogen atmosphere.
particles facilitate their integration with resin matrix.
2.2.5. Differential scanning calorimetry
2.1.3. 3D printing of CCP and AESO coral plugs The glass transition temperature (Tg) of the printed
CCP coral plugs were printed through vat polymerization AESO scaffold was measured using a differential scanning
using a tabletop DLP-based printer (ELEGOO Mars 3). calorimeter from TA Instruments (Discovery 250) at

Volume 3 Issue 2 (2024) 3 doi: 10.36922/msam.3125